The proposed five series of studies have the long-term aim of characterizing age-related differences and similarities in the implicit learning of structural regularities in the environment. By using an alternating serial (visual- spatial) motor response task, where pattern trials alternate with random trials, the investigators will test the hypotheses that when comparing performance of young (18-25 years) and old (65 years and older) the following will occur: (1) age-related deficits will appear in implicit sequence learning, including decreases in the rate and magnitude of learning, in the level of structure that is learned, in the extent to which this knowledge can be used in the absence of stimuli, and in the extent to which it is verbalizable (declarative knowledge); (2) the Alternating Serial Response Time Task will result in unintentional learning, at least partially outside of awareness; (3) the age-related deficits in implicit serial pattern learning will be due in part to age- related decreases in processing deficits, such as slowing and the number of items that can be held simultaneously in working memory and that these age deficits can be simulated in a connectionist modeling network by manipulating the number of events used as input.